The wagons die about 30 seconds or so in. I've reloaded several times. This is after trading - sometimes they died before being able to trade successfully. Four wagons.

I think the issue on Mantis might be 0011446, but it was the mountainhome and I hadn't yet been given the warning about leaving.

The last seen actions of the doomed wagons were "haul amulet" from different bones (one on each wagon).

I had to forbid the depot to force them to leave. Not the greatest workaround as I now have... a lot of stuff I didn't want and not enough haulers.